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(No Medef.) I R. W. 8v F. GRINNELL.

LOGKED JOINT.

No. 277,479. Patented May 15,1883, Fig. l'

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( n I ererzc lGrinnell UNITED STATES RICHARD W.` GRINNELL AND FREDERICK GRINNELL, CF PROVIDENCE PATENT OFFICEm RHODE ISLAND; SAID RICHARD V. GRINNELL ASSIGNOR TO ISAID FREDERICK GRINNELL.

LOCKED JOINT.

SPECIFICATION forming part of Letters Patent No. 277,479, dated May 15, 1883.

Application lil'ed January 22,1883. (No model.)

To all whom 'it may concern Be it known that we, RicHARD W. GRIN- NELL and FREDERICK GRINNELL, both of the city and county of Providence, and State of Rhode Island, have invented a new and useful Improvement in Locked Joints; and we do hereby declare the following to be a full, clear, and exact description 'of the same, reference being had to the accompanying drawings, forming part of this specification.

lntheartofproteotingbuildingsagainstaccidental lires automatically the devices used to extinguish thefir, to sound the alarm, to turn on the water, and other devices, are usuallysecured byjointingtwo parts and holdin gthem together by a solder fusible at a low temperature. Auto matic fire-extinguishers have their valves usually held against the water-pressure by levers, rods, andother devices secured bya solder fusible at a low temperature, andlin the various systems for protecting buildings automatically against tire, valves, wires, weights, and other things are held by parts secured together by easily-fusible solder. l Solder used for such purposes is largely composed of bismuth, and has but small holding-power, particularly when any appreciable thickness of the solder is used; ,and when the temperature is raised, not to the meltingpoint, but abovesay 100O Fahrenheit-the parts are liable to move, as the solders liable to yield. In many cases such yielding destroys the utility of the devices-as, for instance, Where a valve in an automatic fire-extinguisher is held to its seat by such a soldered joint and the joint yields theleast, then the valve will leak, and the by a fusible solder, as will be more iully set forth hereinafter.

Y Figure l is a sectional View of two parts secured together by a key so as to resist strain. Fig. 2 is a sectional view of two parts secured together by a key constructed to resist thrust. Fig. 3 is a sectional view of a modified form constructed to resist strain. Fig. 4 is a perspective view of a modification in which the key is arranged to resist either strain or compression, and Fig. 5 is a sectional view of the same.

In the drawings, a a are two parts of an automatic fire-extinguisher, of a link or any other device that is to resist either compressive or tensile strain, and is to be released in case of a fire by the action of heat on afusible solder. b is a metal key inserted so as to lock the two parts and retain them in the desired position, thereby interposing a metal locking device on which the parts a a exert a shearing strain. The key b is provided with the flange c, and this flange is soldered to one of the pieces c a, to keep the key in place until on the occurrence ot' are the solder melts and releases the key, which is then free to yield to the strain on the parts a c and release the same. c1 d are holes made into the parts a c to receive the key b. These holes are somewhat longer than the Width of the key b, so that when released the key can tilt and allow the parts to separate.

The device shown in Figs. 4 and 5 consists of a key having two beveled surfaces, which is inserted into beveled recesses formed in the parts a a to lock the same. As soon as the key is released the strain throws it out of the recesses and releases the parts. A lip, e, is formed'on one of the parts c; but when these parts form `xed parts of a device such lip isI not required.

It will be seen that all the strain is resisted by the key b, and that the parts are securely locked, metal to metal, as long as the key .is held in place by the solder. By properly proportioning the parts any amount of resistance can be secured, which cannot have the slightest motion until the key is released, formby the action of heat and permit the parts to 1o ing a. perfectly-locked joint. separate, as described.

Having thus described our invention, we 2. The combination, with the parts a a, of claim as new and desire to secure by Letters. the key b, secured by solder, as described.

5 Patentv v RICHARD W. GRINNELL.

I. In devices used for protection against f FREDERICK GRINNELL. fire, the combination, with two parts'adapted Witnesses: y to resist strain, of a. key placed so as to secure J. A. MILLER, J r.

the parts together, constructed to be released M. F. BLIGH. 

